The rotator cuff is a muscle group surrounding the shoulder joint. Its primary purpose is to stabilize and strengthen the joint and to enable rotation of the arm.
Rotator cuff exercising devices are known in the prior art. For example, U.S. Pat. No. 4,553,747 to Pursley describes one such machine that includes an upright support frame and first and second body support members spaced from the upright support member along a plane parallel thereto. The first body support member is a seat upon which the user is seated and the second body support member receives the user's upper arm. Because the first and second support members are located in the same parallel plane, the rotator cuff muscle group can be isolated. The exercise machine shown in the Pursley patent also includes a handle attached to a cable that is, in turn, connected to one or more weights. When the user is properly positioned in the seat with his or her arm in the second body support member, the handle is grasped and moved against the pull of the weights to thereby enable external and internal rotation in abduction exercises. In an alternate embodiment, the seat is removed and the user stands at a 90 degree angle with respect to the machine to thereby enable external and internal rotation to adduction exercises.
While the machine described in the Pursley patent does provide isolation of the rotator cuff, the user's forearm is unsupported and thus must be carefully controlled during the exercises to retain this isolation. Moreover, because the forearm is not supported, the exercises can put additional stress on the wrist and elbow. It would therefore be desirable to provide a rotator cuff exercise machine that isolates the rotator cuff muscle group, yet can provide effective and comfortable support of the forearm during the rotator cuff exercises.